On a representative atomistic volume for a grain embedded in a polycrystal

► A new concept of a representative atomistic volume for a grain (RAVG) is proposed. ► The validity of this concept is investigated numerically. ► It is found that the grain size of 12 lattice units (3.4 nm, 3250 atoms) is sufficient to be a RAVG. ► The RAVG is the first step in identifying a representative atomistic volume for a polycrystal (RAVP).